You could do that, but why? You would shut off the rear brake line, but would still have to hold the brake pedal down to lock your front brakes to do your burnout.

Well, that is where the "whatnot" comes in play, i would also like to be able to play around.... say rolling at about 25-30mph, lock the back brakes out so they dont catch, and start feathering the front along with throttle for a rolling burnout. Again all just for play.